Effects of thidiazuron on the quality and storage properties of mango fruit during postharvest

Thidiazuron (TDZ) is used for the expansion of fruits, but excessive levels of TDZ lead to a decline in fruit quality. The appropriate concentration of TDZ for mango expansion without a decline in quality is not clear. In the present study, four different concentrations (5, 10, 15, and 20 mg/L) of TDZ were applied via spraying on mango plants, and several physiological and biochemical indicators were measured. The results showed that TDZ treatment significantly increased mango fruit size and single-fruit weight. In mango fruit, TDZ treatment decreased the disease index, delayed the increase in the malondialdehyde and H2O2 content, and maintained firmness and antioxidant capacities at a relatively high level during postharvest storage. At the same time, TDZ treatment delayed the decrease in the giberellin, indoleacetic acid and jasmonic acid content in mango, and reduced the accumulation of abscisic acid and ethylene. These trends are consistent with TDZ treatment leading to extension of the shelf life of mango. Furthermore, ethylene biosynthesis, signal transduction, and cell wall dismantling-related genes were investigated. The results indicated that the expression of the MiACS, MiETR2, MiERF113, MiERF010, MiERF054, MiEXP, MiPG14, MiPG21, MiCEL, and MiPEL genes in mango was inhibited under TDZ treatment compared with the control. In summary, TDZ treatment can significantly increase the size and weight of mango fruit and can extend its shelf life. The most suitable concentration is 10-15 mg/L TDZ, which will not affect the quality of mango fruit.